Lamp



FIG. 1 is a perspective view of the design for a lamp as seen from the front, top;

FIG. 2 is a front elevational view thereof, the rear and side views being similar;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof.

The broken line disclosure is for environmental purposes only and does not form a part of the claimed design. 

CLAIM The ornamental design for a lamp, as shown and described. 